Changes in the essential oil content and terpene composition of rosemary (Rosmarinus officinalis L.) by using plant biostimulants

Plant biostimulants can stimulate the increase of growth, metabolism and the biosynthesis of metabolites in plants. This study investigated the changes of rosemary essential oil and its components composition under use of biostimulants for the possible reduction in use of chemical fertilizers. Treatments included biostimulants based on amino acids in four formulations, Aminolforte, Kadostim, Humiforte, and Fosnutren (each of them at 0.75 and 1.5 L ha^-1), and application of N.P.K fertilizer as a control treatment (by applied complete fertilizer at 100 kg per hectar with proportion of 15:8:15 percentage of N:P:K in the fertilizer). Results showed that the essential oil content and its components were significantly affected by biostimulants application. The maximum content of essential oil was obtained at 1.5 L ha^-1 Humiforte and both concentrations of Aminolforte. While, the highest content of α-pinene, 1,8- cineole, and camphor as major components of rosemary essential oil were obtained at 1.5 L ha^-1 Fosnutren. In addition, the maximum content of linalool, z-pinocamphone, bornyl acetate, and caryophyllene oxide were observed at 1.5 L ha^-1 Fosnutren. Although, the highest content of myrcene and verbenone was obtained in the treatment with N.P.K fertilizer, but the maximum contents of β-pinene, camphene, borneol, and α-terpineol were related to the both concentrations of Aminolforte. We can conclude that biostimulants based on amino acids can be an effective alternative in reducing the use of chemical fertilizer and increasing the quantity and quality of rosemary essential oil.